With wins over the big three of world tennis already under his belt in 2019, Greek star Stefanos Tsitsipas said on Thursday he believed he had the ammunition to take the world number one ranking.

Tsitsipas became the youngest player to beat Rafael Nadal on clay and the youngest to record wins over Nadal, Roger Federer and Novak Djokovic during a stellar 2019 which saw him rise to world number five.

The 21-year-old heads into the inaugural ATP Cup ranked sixth, but said he was confident he could go all the way to the top.

“I mean, yeah, they are still there -- they are doing really well,” Tsitsipas said about Nadal, Federer and Djokovic.

“For me, it’s very challenging to go out there and compete against them.

“I feel like there’s something extra to chase after when I play against them, plus I get to learn a lot when I play against them.

“I feel more of a complete player,” he added.

“I kind of compare them to me to see what works for them and what should I work on more, and they’re just super humans in a way.

“But I’m trying to get there myself and I’m going to keep trying to do my best because I feel like I can surpass them, I can be better.

“It’s just a matter of time, patience, and dedication on what I do.”

Tsitsipas said he was in top shape heading into the new season and said he was playing pain free.

But he conceded he needed to work on his consistency across tournaments.

“I improved during my pre-season -- I feel like I’ve added a few elements in my game,” he said.

“Obviously, ups and downs, you can’t be consistent all the time (but) I’m going to try to be consistent as much as possible.

“I’m going to try to be even better than I was last year, but in the back of my mind I’ve concentrated on having a consistent balanced well-planned year with not many ups and downs.”

Tsitsipas gets his tournament underway against rising Canadian star Dennis Shapovalov on Friday morning.

Meanwhile, world number four Dominic Thiem on Thursday expressed confidence a new Grand Slam champion will be crowned in 2020 outside the big three of Novak Djokovic, Rafael Nadal and Roger Federer.

While the Austrian, Germany’s Alexander Zverev, Greece’s Stefanos Tsitsipas and others have had success at lesser tournaments, the big guns continue to dominate the majors.

Thiem, in Sydney for the inaugural ATP Cup team event, is one of the men tipped to make the breakthrough, with the first Grand Slam of the year, the Australian Open, just weeks away in Melbourne.

He said the younger players were getting close.

“I think we challenged them already a lot. We also beat them especially on Masters 1000 stages and the ATP Finals,” said Thiem, who was runner-up to Tsitsipas at the ATP Finals in London in November.

“I think the last stage we have to conquer is the Grand Slam stage, and I really think we’ll see a new Grand Slam champion in 2020.

“I really hope that it’s me, but you cannot guarantee anything. There are also many other very strong guys who can achieve that.

“Maybe it’s also not happening and Big Three are taking all four,” he added.

“But we are trying everything to achieve top position, to achieve the biggest titles, Grand Slam titles.”

Thiem, 26, won five titles last year at Indian Wells, Barcelona, Kitzbuhel, Beijing and Vienna, but he had a mixed time at the majors, falling at the first hurdle at Wimbledon and the US Open and in the second round in Australia.

However, he reached the final at Roland Garros, only to be beaten by clay king Nadal.

“I was really happy how my game developed, especially in the last part of the season in 2019,” he said.

“I’ll try everything to do my best this year.”

Agence France-Presse